Also, I have a family of 4 (2 adults, a 7 yr old, and a 2 yr old), it this big enough for us?
Depends on what & how much stuff you bring, and how long your typical trip is.
I have a 43 qt Edgestar fridge that's been sufficient room for two people for 10-14 days... It does take a bit of thought while packing (nestling) everything in place, but can be done (repackaging items from bulky packaging into ziploc baggies helps). Certainly you can't pack your entire beer and/or soda stash in it though, but it is possible to keep maybe 4 cans/bottles in there and feed new ones in as you drink the cold ones (or you could also bring a separate cooler w/ice for your chilled nonperishables).
Stuff I typically pack in the fridge for a week or longer trip (just to give you some idea):
2-3lbs hamburger/hamburger patties
2-3lbs steaks
1lb chicken
1-2 pkgs hot dogs
3-4lbs bacon & sausage
3 doz eggs
1-2lbs sandwich (lunch) meat
1lb sliced cheeses
3 sticks butter
Mayo (small squeeze-type bottle)
2 cartons milk (½ gallon ea)
1 large (6.8 oz) Hershey Special Dark bar
Stuff like ketchup, mustard, and taco sauce I don't pack in the fridge... Instead I grab a handful of the little packets from various fast-food places which don't need to be refrigerated. Occasionally I'll find mayo packets too (this will save the bottle of mayo in the fridge), though finding mayo packets isn't as easy as the others. Apples, nectarines, tomatoes, etc. ride separate also.